Phyrexian ObliteratorHow it works & interactions with other cards

Unpacking the Ability

Phyrexian Obliterator features a triggered ability that responds to any source of damage. Whether it is combat damage, a spell like a fireball, or an ability, the source's controller must sacrifice permanents equal to the amount of damage dealt. Because this is a triggered ability using the word 'whenever,' it goes on the stack after the damage has already been processed.

Step-by-Step Resolution

First, the damage is dealt to Phyrexian Obliterator, and its ability triggers. Second, state-based actions are checked; if the Obliterator took lethal damage, it is moved to the graveyard. Third, the trigger is placed on the stack. Finally, when the trigger resolves, the opponent chooses which permanents to sacrifice. Crucially, they cannot sacrifice creatures that were already destroyed by combat damage in the same step, as those are already gone.

Strategic Timing

The best time to utilize Phyrexian Obliterator is against aggressive decks that rely on ground-based combat. Its Trample ensures that your opponent cannot simply chump-block with small tokens to stay safe. If they do block, they still take excess damage and must sacrifice permanents. It is most effective when your opponent is low on resources, as a single hit can completely wipe their board presence.

Common Pitfalls

A common mistake is forgetting that the Obliterator's controller does not choose what is sacrificed; the source's controller chooses. Also, keep in mind that 'loss of life' is not damage. Spells that cause a player to lose life will not trigger the ability. Furthermore, if damage is prevented (by a protection effect, for example), the ability will not trigger because no damage was actually dealt.

Interaction examples

Blocking for Value

Solemn Simulacrum

If your opponent attacks you with a Solemn Simulacrum and you block with Phyrexian Obliterator, the Simulacrum deals 2 damage to the Obliterator. After combat, the Obliterator's trigger goes on the stack. The opponent must sacrifice two permanents. Note that they cannot sacrifice the Solemn Simulacrum itself to satisfy the trigger, as it died during combat before the trigger resolved.

Doubling the Horror

Roaming Throne

If you control Roaming Throne and chose 'Phyrexian' as it entered, its static ability will apply to Phyrexian Obliterator. If a source deals 3 damage to your Obliterator, the ability triggers twice. The opponent will have to sacrifice 3 permanents for the first trigger, and then another 3 permanents for the second trigger, resulting in a total loss of 6 permanents.